Load index.html every time from the server and NOT from cache - html

I have a webpage index.html hosted on a particular server. I have pointed example.com to example.com/index.html. So when I make changes in index.html and save it, and then try to open example.com, the changes are not reflected. Reason that the webpages are being cached.
Then I manually refresh the page and since it loads the fresh copies and not from cache, it works fine. But I cannot ask my client to do so, and they want everything to be perfect. So my question is that is there a trick or technique as to how I can make the file load every time from the server and not from cache?
P.S: I know the trick for CSS, JS and images files, i.e. appending ?v=1 but don't know how to do it for index.html.
Any help would be appreciated. Thanks!

by this:
<meta http-equiv="expires" content="0">
Setting the content to "0" tells the browsers to always load the page from the web server.

The meta tags didn't worked for me so. i set the headers from the java class that implements filter or controller. and it worked. here is the code
HttpServletResponse httpResponse = (HttpServletResponse) response;
httpResponse.setHeader("Cache-Control", "no-cache, no-store, must-revalidate"); // HTTP 1.1
httpResponse.setHeader("Pragma", "no-cache"); // HTTP 1.0
httpResponse.setDateHeader("Expires", 0); // Proxies.

There are only two most reliable way available as of 2018
1) **<meta http-equiv="expires" content="0">** Use this meta tag but be careful because this tag destroy the all cache of the page as soon as a web page processed by browser.
2) Generate an unique ID at server for each page request and append this id at the end of the all file name inside the HTML document with ? before the unique id append on images, documents, css/js files, videos etc which need to be load from the server every time. For example if you have the HTML tag like <img src="images/profile223.jpg" alt="profile picture"> then on server side append the unique id at the end of the file name like this echo '<img src="images/profile223.jpg?'.$uniqueid.'"" alt="profile picture">'; . In this example i use php but you can generate the unique ID on any language. All big companies like Google, Facebook, Microsoft, Twitter etc. uses this technique because it is most effective way and does not effect the cache data you want to store on user browser like login session id. This technique is cross browser compatible and support older version of IE, Firefox, Chrome, Safari and Opera. You may append the unique id at the end of the url using the same technique

You can try this below method. It worked for me.
Please add the below lines of code in your .htaccess file.
<IfModule mod_headers.c>
<FilesMatch "\.(html|php)$">
Header set Cache-Control "no-cache, no-store, must-revalidate"
Header set Pragma "no-cache"
Header set Expires 0
</FilesMatch>
<FilesMatch "\.(ico|pdf|jpg|png|gif|js|css)$">
Header set Cache-Control "max-age=172800, public, must-revalidate"
</FilesMatch>
</IfModule>
If you use the above code, browser will not cache .html files.

Adding this meta tags to the header works for most of the browsers (in that case index.html will not be cached):
<meta http-equiv="cache-control" content="max-age=0" />
<meta http-equiv="cache-control" content="no-cache" />
<meta http-equiv="expires" content="0" />
<meta http-equiv="expires" content="Tue, 01 Jan 1980 1:00:00 GMT" />
<meta http-equiv="pragma" content="no-cache" />
A bit late but it might help someone else!

You can send extra headers with the file to tell the client (the browser, that is) that the file must not be cached. If you got Apache, take a look at mod_expires. If you use a server side scripting language, like PHP, you can solve it using that too.

i ever meet this problem with my website. in your URL add the q=''
http://yoururl.com/somelinks?q=fill_with_random_number
for me, it works

I highly recommend not using meta tags and use htaccess as Murali Krishna Bellamkonda posted. That will always be the best and most secure dependable way. You can fine tune your whole system to stay cached for long times, refresh files at specific times, etc...
Go ahead and try all them meta tags at once, and see what happens! (no I wouldnt)
Look into Header set Cache-Control "max-age=5, immutable" with ExpiresDefault A5 for a no cache option.

Related

Prevent Browser File Caching

I need to disable caching for single files in all browsers.
I have a website that generates small video clips. There is a preview stage where the results can be watched.
An mp4 called preview.mp4 is displayed. When the user goes back, edits the video and wants to preview it again, the old preview.mp4 is being displayed even though the file on the server is changed.
How can I prevent the caching of this video file? Or what are the other ways to fix it?
Note: it's a single page application so I don't reload any HTML files. Only PHP content. Hence the headers I set, are not useful in this scenario:
<meta http-equiv="X-UA-Compatible" content="IE=Edge"/>
<meta http-equiv="cache-control" content="no-store" />
Thanks.
It's not the web page itself you should be concerned about, but the mp4 file which is downloaded and cached separately.
Ensure the response headers of the mp4 file prevent browser caching.
Cache-Control: no-cache
Hence the headers I set, are not useful in this scenario:
<meta http-equiv="cache-control" content="no-store" />
There problem here is that those are not headers.
They are HTML elements (which are part of the HTML document, which is the body of the HTTP response) which attempt to be equivalent to HTTP headers … and fail.
You need to set real HTTP headers, and you need to send them with the video file (rather than the HTML document).
The specifics of how you do that will depend on the HTTP server you use.
Further reading:
Caching in the HTTP specification
Caching Tutorial for Web Authors and Webmasters
Caching Guide in the Apache HTTPD manual
How to Modify the Cache-Control HTTP Header When You Use IIS
Try adding a cache key
preview.mp4?cachekey=randNum
Where randNum can be a timestamp or you use a random number generator to generate randNum.

Can we add http response headers directly into html pages

I need to add response headers like X-Frame, Cache-control, Pragma etc directly into the html code, may be, using attributes in html elements?
It is for help pages which are directly coming from a directory via href link.
Is there any way to add headers to these htmls?
You can use meta to replicate some of these. Normally not the ideal solution, but look into the http-equiv attribute of meta tags. I believe a lot of these have been deprecated in newer browsers.
Examples:
<meta http-equiv="Cache-control" content="no-cache"/>
<meta http-equiv="X-Frame-Options" content="sameorigin"/>
<meta http-equiv="pragma" content="no-cache"/>
In short: no, you cannot. HTML files are the body of an HTTP response; the headers must come from the server. Anything you could embed in the HTML file would just become part of the body.
You can add something like this, if php execution is enabled on your web server:
<?php
http_response_code(your_response_code)
?>
rest-of-your-html-code
This will execute a php script that will set the response code.

Website doesn't update when accessed, unless page is refreshed

I have an HTML document that is on a local server (not a webserver, if that's important). Sometimes, after updating some files, I go to visit the HTML document and it is not updated. However, if I try to refresh the page, the content then updates.
I'm not sure why this is occurring considering that I am opening the page anyway after update, so it should have the latest values then.
The issue is that browser is caching the HTML document it self. It is fine for static pages, where data remains constant
but as you stated that content of the page is dynamic, you can do 2 things
Add expiration header for document via server side code. This ensures that when ever user tries to access your page, the browser always sends a request to server and ignores local cache. Some of the headers you need to set
Cache-Control : no-cache, no-store, must-revalidate
Expires : -1
Pragma : no-cache
Add expiration via meta tags
<meta http-equiv="expires" content="Fri,31 Dec 2010 11:59:59 GMT" />
<meta http-equiv="cache-control" content="no-cache">
This should be kept under <head> tag

New webpage not being shown

I have a web development question.
Sometimes, if I place a new version of a webpage on a webserver, and I browse to this webpage, the new page is not shown. Instead the old page is shown, from the cached page from a previous browse to the webpage.
How can I get the new page to always be shown? Is there a tag of some sort that I can use for this?
There are some tags you can use
See http://www.i18nguy.com/markup/metatags.html
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
<META HTTP-EQUIV="EXPIRES" CONTENT="0">
<META HTTP-EQUIV="PRAGMA" CONTENT="NO-CACHE">
There are similar HTTP headers that the web server can set as well.
Yes, you can specify no caching and how long to cache individual files in .htaccess if you are using Apache. Typically you would disable caching on dynamic content and set caching limits to the usual update rate of images and static html. On my site I regenerate the static html every day so have set caching to 24 hours on .html and disabled caching on PHP scripts (these limits are specified in seconds - 1 day = 86,400 seconds):
# Set up caching on media files for 1 week
<FilesMatch "\.(gif|jpg|jpeg|png|js|css)$">
ExpiresDefault A604800
Header append Cache-Control "public"
</FilesMatch>
# Set up 1 Day caching on site generated files
<FilesMatch "\.(xml|txt|html)$">
ExpiresDefault A86400
Header append Cache-Control "proxy-revalidate"
</FilesMatch>
# Force no caching for dynamic php
<FilesMatch "\.php$">
ExpiresActive Off
Header set Cache-Control "private, no-cache, no-store, proxy-revalidate, no-transform"
Header set Pragma "no-cache"
</FilesMatch>
If you are just having problems testing changes to your html files, remember that you can usually force a browser to reload the page regardless of cache settings - [Ctrl][F5] under Windows.
I think the server still haven't update the site. Just wait and see if it updates.

Google Chrome Cache

I have an html page that embeds a flash (flex) application.
I have the following headers:
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-CACHE">
<META HTTP-EQUIV="CACHE-CONTROL" CONTENT="NO-STORE">
<META HTTP-EQUIV="Pragma" CONTENT="no-cache">
<META HTTP-EQUIV="Expires" CONTENT="-1">
In addition, each time I release a new version of the app, I change the file name. So, it becomes something like MyApp_v1.swf, which is then updated to MyApp_v2.swf.
Despite this, chrome still caches the html page and the swf file. This is a major problem, as clients do not then see the updated swf unless they clear their browser cache.
I even tried to get around this with changing the htaccess file, and renaming the index.html file that hosts the swf file:
RewriteEngine On
RewriteCond %{HTTPS} !=on
RewriteRule ^(.*)$ https://www.mysite.com/app[R,L]
DirectoryIndex index.html #this was changed from myapp.html
Even after doing this, Chrome still caches the swf, and is STILL reading from the old html file. I do a view source on the html, and its still showing the old file.
This all works fine in any other browser.
These two bug reports relate, some good relevant information in here:
Issue 28035 - chromium - Cache doesn't adhear to No cache options ( google crome )
Issue 64139 - chromium - Cache isn't revalidated properly, no-cache directive
Another solution may be to add specific cache-control or pragma HTTP headers as mentioned in the links above
Also, dumb question, did you clear chrome cache before testing your <meta> no-cache tags? wondering if it is still using cache from before your changes.
For all you guys struggeling with this
i found something simple that works...
i tried
1. ctrl + f5
2. ctrl + shift + 5
3. setting the "no cache" in developer tools..
What worked for me in the end is to
Just hold the CTRL key while you click the reload icon!
Use this "no-store" extra tag, and the cache works fine in Chromium (Chrome) as in the other capable browsers:
header("Cache-Control: no-cache, no-store, must-revalidate");
header("Pragma: no-cache, no-store");